[tor-commits] [tor/master] Fetch the current consensus from the conscache subsystem.
nickm at torproject.org
nickm at torproject.org
Mon May 15 21:26:28 UTC 2017
commit ef2a62b2ff0c8db17e146a79034c8e43ee528c86
Author: Alexander Færøy <ahf at torproject.org>
Date: Fri May 12 21:17:09 2017 +0200
Fetch the current consensus from the conscache subsystem.
This patch changes handle_get_current_consensus() to make it read the
current consensus document from the consensus caching subsystem.
See: https://bugs.torproject.org/21667
---
src/or/directory.c | 121 ++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 88 insertions(+), 33 deletions(-)
diff --git a/src/or/directory.c b/src/or/directory.c
index 4a528f2..946792b 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -13,6 +13,7 @@
#include "config.h"
#include "connection.h"
#include "connection_edge.h"
+#include "conscache.h"
#include "consdiff.h"
#include "consdiffmgr.h"
#include "control.h"
@@ -117,7 +118,8 @@ static void dir_routerdesc_download_failed(smartlist_t *failed,
int was_descriptor_digests);
static void dir_microdesc_download_failed(smartlist_t *failed,
int status_code);
-static int client_likes_consensus(networkstatus_t *v, const char *want_url);
+static int client_likes_consensus(const struct consensus_cache_entry_t *ent,
+ const char *want_url);
static void connection_dir_close_consensus_fetches(
dir_connection_t *except_this_one, const char *resource);
@@ -3377,14 +3379,20 @@ accept_encoding_header(void)
* consensus, 0 otherwise.
*/
int
-client_likes_consensus(networkstatus_t *v, const char *want_url)
+client_likes_consensus(const struct consensus_cache_entry_t *ent,
+ const char *want_url)
{
smartlist_t *want_authorities = smartlist_new();
+ smartlist_t *voters = smartlist_new();
int need_at_least;
int have = 0;
dir_split_resource_into_fingerprints(want_url, want_authorities, NULL, 0);
need_at_least = smartlist_len(want_authorities)/2+1;
+
+ if (consensus_cache_entry_get_voters(ent, voters) != 0)
+ goto done;
+
SMARTLIST_FOREACH_BEGIN(want_authorities, const char *, d) {
char want_digest[DIGEST_LEN];
size_t want_len = strlen(d)/2;
@@ -3398,7 +3406,7 @@ client_likes_consensus(networkstatus_t *v, const char *want_url)
continue;
};
- SMARTLIST_FOREACH_BEGIN(v->voters, networkstatus_voter_info_t *, vi) {
+ SMARTLIST_FOREACH_BEGIN(voters, networkstatus_voter_info_t *, vi) {
if (smartlist_len(vi->sigs) &&
tor_memeq(vi->identity_digest, want_digest, want_len)) {
have++;
@@ -3411,8 +3419,11 @@ client_likes_consensus(networkstatus_t *v, const char *want_url)
break;
} SMARTLIST_FOREACH_END(d);
+ done:
SMARTLIST_FOREACH(want_authorities, char *, d, tor_free(d));
smartlist_free(want_authorities);
+ SMARTLIST_FOREACH(voters, networkstatus_voter_info_t *, v, tor_free(v));
+ smartlist_free(voters);
return (have >= need_at_least);
}
@@ -3619,20 +3630,25 @@ handle_get_frontpage(dir_connection_t *conn, const get_handler_args_t *args)
return 0;
}
-/** Warn that the consensus <b>v</b> of type <b>flavor</b> is too old and will
- * not be served to clients. Rate-limit the warning to avoid logging an entry
- * on every request.
+/** Warn that the cached consensus <b>cached_consensus</b> of type
+ * <b>flavor</b> is too old and will not be served to clients. Rate-limit the
+ * warning to avoid logging an entry on every request.
*/
static void
-warn_consensus_is_too_old(networkstatus_t *v, const char *flavor, time_t now)
+warn_consensus_is_too_old(const struct consensus_cache_entry_t *cached_consensus,
+ const char *flavor, time_t now)
{
#define TOO_OLD_WARNING_INTERVAL (60*60)
static ratelim_t warned = RATELIM_INIT(TOO_OLD_WARNING_INTERVAL);
char timestamp[ISO_TIME_LEN+1];
+ time_t valid_until;
char *dupes;
+ if (consensus_cache_entry_valid_until(cached_consensus, &valid_until))
+ return;
+
if ((dupes = rate_limit_log(&warned, now))) {
- format_local_iso_time(timestamp, v->valid_until);
+ format_local_iso_time(timestamp, valid_until);
log_warn(LD_DIRSERV, "Our %s%sconsensus is too old, so we will not "
"serve it to clients. It was valid until %s local time and we "
"continued to serve it for up to 24 hours after it expired.%s",
@@ -3705,6 +3721,35 @@ find_best_diff(const smartlist_t *digests, int flav,
return NULL;
}
+/** Lookup the cached consensus document by the flavor found in <b>flav</b>.
+ * The prefered set of compression methods should be listed in the
+ * <b>compression_methods</b> bitfield. The compression method chosen (if any)
+ * is stored in <b>compression_used_out</b>. */
+static struct consensus_cache_entry_t *
+find_best_consensus(int flav,
+ unsigned compression_methods,
+ compress_method_t *compression_used_out)
+{
+ struct consensus_cache_entry_t *result = NULL;
+ unsigned u;
+
+ for (u = 0; u < ARRAY_LENGTH(srv_meth_pref_precompressed); ++u) {
+ compress_method_t method = srv_meth_pref_precompressed[u];
+
+ if (0 == (compression_methods & (1u<<method)))
+ continue;
+
+ if (consdiffmgr_find_consensus(&result, flav,
+ method) == CONSDIFF_AVAILABLE) {
+ tor_assert_nonfatal(result);
+ *compression_used_out = method;
+ return result;
+ }
+ }
+
+ return NULL;
+}
+
/** Try to find the best supported compression method possible from a given
* <b>compression_methods</b>. Return NO_METHOD if no mutually supported
* compression method could be found. */
@@ -3747,7 +3792,6 @@ handle_get_current_consensus(dir_connection_t *conn,
/* v3 network status fetch. */
long lifetime = NETWORKSTATUS_CACHE_LIFETIME;
- networkstatus_t *v;
time_t now = time(NULL);
const char *want_fps = NULL;
char *flavor = NULL;
@@ -3773,18 +3817,33 @@ handle_get_current_consensus(dir_connection_t *conn,
want_fps = url+strlen(CONSENSUS_URL_PREFIX);
}
- v = networkstatus_get_latest_consensus_by_flavor(flav);
+ struct consensus_cache_entry_t *cached_consensus = NULL;
+ smartlist_t *diff_from_digests = NULL;
+ compress_method_t compression_used = NO_METHOD;
+ if (!parse_or_diff_from_header(&diff_from_digests, args->headers)) {
+ tor_assert(diff_from_digests);
+ cached_consensus = find_best_diff(diff_from_digests, flav,
+ args->compression_supported,
+ &compression_used);
+ SMARTLIST_FOREACH(diff_from_digests, uint8_t *, d, tor_free(d));
+ smartlist_free(diff_from_digests);
+ } else {
+ cached_consensus = find_best_consensus(flav,
+ args->compression_supported,
+ &compression_used);
+ }
- if (v && !networkstatus_consensus_reasonably_live(v, now)) {
+ if (cached_consensus &&
+ !consensus_cache_entry_is_reasonably_live(cached_consensus, now)) {
write_http_status_line(conn, 404, "Consensus is too old");
- warn_consensus_is_too_old(v, flavor, now);
+ warn_consensus_is_too_old(cached_consensus, flavor, now);
geoip_note_ns_response(GEOIP_REJECT_NOT_FOUND);
tor_free(flavor);
goto done;
}
- if (v && want_fps &&
- !client_likes_consensus(v, want_fps)) {
+ if (cached_consensus && want_fps &&
+ !client_likes_consensus(cached_consensus, want_fps)) {
write_http_status_line(conn, 404, "Consensus not signed by sufficient "
"number of requested authorities");
geoip_note_ns_response(GEOIP_REJECT_NOT_ENOUGH_SIGS);
@@ -3792,37 +3851,30 @@ handle_get_current_consensus(dir_connection_t *conn,
goto done;
}
- struct consensus_cache_entry_t *cached_diff = NULL;
- smartlist_t *diff_from_digests = NULL;
- compress_method_t compression_used = NO_METHOD;
- if (!parse_or_diff_from_header(&diff_from_digests, args->headers)) {
- tor_assert(diff_from_digests);
- cached_diff = find_best_diff(diff_from_digests, flav,
- args->compression_supported,
- &compression_used);
- SMARTLIST_FOREACH(diff_from_digests, uint8_t *, d, tor_free(d));
- smartlist_free(diff_from_digests);
- }
-
conn->spool = smartlist_new();
clear_spool = 1;
{
spooled_resource_t *spooled;
- if (cached_diff) {
- spooled = spooled_resource_new_from_cache_entry(cached_diff);
+ if (cached_consensus) {
+ spooled = spooled_resource_new_from_cache_entry(cached_consensus);
} else if (flavor) {
spooled = spooled_resource_new(DIR_SPOOL_NETWORKSTATUS,
(uint8_t*)flavor, strlen(flavor));
- compression_used = compress_method;
+ compression_used = ZLIB_METHOD;
} else {
spooled = spooled_resource_new(DIR_SPOOL_NETWORKSTATUS,
NULL, 0);
- compression_used = compress_method;
+ compression_used = ZLIB_METHOD;
}
tor_free(flavor);
smartlist_add(conn->spool, spooled);
}
- lifetime = (v && v->fresh_until > now) ? v->fresh_until - now : 0;
+
+ if (cached_consensus &&
+ consensus_cache_entry_get_lifetime(cached_consensus,
+ &lifetime) != 0) {
+ lifetime = 0;
+ }
if (!smartlist_len(conn->spool)) { /* we failed to create/cache cp */
write_http_status_line(conn, 503, "Network status object unavailable");
@@ -3875,8 +3927,11 @@ handle_get_current_consensus(dir_connection_t *conn,
write_http_response_header(conn, -1,
compression_used,
smartlist_len(conn->spool) == 1 ? lifetime : 0);
- if (compress_method != NO_METHOD)
- conn->compress_state = tor_compress_new(0, compress_method,
+
+ // The compress_method requested was NO_METHOD, but we store the data
+ // compressed. Decompress them using `compression_used`.
+ if (compress_method == NO_METHOD)
+ conn->compress_state = tor_compress_new(0, compression_used,
HIGH_COMPRESSION);
/* Prime the connection with some data. */
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